Methods and systems to monitor and control crude oil processing with regards to crude oil specifications for bottom sediment & water (BS&W) and salt are provided. Crude oil processing may be monitored and controlled using key performance indicators (KPIs) that include the desalter voltage and dehydrator voltage as indicators of the BS&W and salt. In response to monitoring of the desalter voltage and dehydrator voltage, a high pressure production trap (HPPT) efficiency and a dehydrator separation efficiency may be controlled via adjustment of a wash water percentage, a demulsifier dosage, a dehydrator interface level, a desalter interface level, and a differential pressure across a mixing valve.